1. Field of the Invention
The present invention relates to a thermal printer that uses a thermal paper sheet having heat-sensitive layers on both surfaces thereof, and a method of controlling the same.
2. Description of the Related Art
A thermal paper sheet used in a thermal printer has a heat-sensitive layer on one surface thereof. In accordance with this structure, a thermal printer prints printing data input from the outside on one surface of a thermal paper sheet by using a single thermal head. The printed thermal paper sheet is cut by a cutter and provided to a user.
When an amount of printing data input from the outside is large, a thermal paper sheet on which the data is to be printed becomes long and hence it is difficult to handle by a user.
On the other hand, a thermal paper sheet having heat-sensitive layers on both surfaces thereof has been recently developed. In order to print data on both surfaces of the thermal paper sheet, there is required processing of, e.g., feeding a paper sheet to an image forming portion of a photosensitive drum or a development unit to form an image on a first surface of the paper sheet, returning the paper sheet having the image formed thereon to the image forming portion while reversing the paper sheet, and forming an image of a second surface of the paper sheet by the image forming portion, as in double-side copying in a copying machine (see, e.g., Jpn. Pat. Appln. KOKAI Publication No. 233256-1997 and Jpn. Pat. Appln. KOKAI Publication No. 24082-1994).
However, the processing similar to a copying machine takes time, and it cannot be applied to a thermal printer used for issuing a sales receipt to a customer at, e.g., a store.